The present invention relates to a method of magnetizing a rotor magnet of a reluctance magnet motor. The method of magnetizing comprises two steps: first, electric current is fed to a stator coil to position a rotor at a magnetizing position by a reluctance torque, and then, electric current is fed to the stator coil to magnetize a rotor magnet.
FIG. 10 is a drawing from a Japanese Patent Application (Publication No. S57-14261), which depicts how a stator coil is used for both positioning and magnetizing a rotor. According to S57-14261, a magnetic pole that has been weakened by some accident is remagentized. A rotor 2 comprises a rotor core 2a, a rotor magnet 3d made of permanent magnet, and a stainless tube 7, which prevents breakage of the rotor magnet 3d due to centrifugal force. Since the reluctance of the rotor 2 is equal in all radial directions, this motor generates only magnet torque, and does not generate reluctance torque. The rotor magnet 3d has weakened magnetic poles N and S. First, as shown in FIG. 10(a), positioning current Ip is fed from a positioning power supply 9a to the outer terminals R and S of the stator, thereby generating stator field E. Then the rotor 2 is rotated by the magnet torque produced between the stator field E and the magnetic poles N and S. The rotor 2 is rotated to a position where the magnetic poles N and S, and the stator field E, are oriented in the same direction. Next, as shown in FIG. 10(b), magnetizing current Im is fed from a magnetizing power supply 9b to the outer terminals T and S of the stator, thereby producing magnetized field G as stator field. Then, the rotor 2 is remagnetized by the magnetizing field G while rotating in the direction of the arrow driven by the magnetic torque produced between the magnetized field G and the magnetic poles N and S. The rotation of the rotor is utilized for widening a magnetizing width over the coil pitch of the stator winding.